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-   -   what is max boost (https://sprinter-source.com/forum/showthread.php?t=77518)

mickal 07-08-2019 03:56 PM

what is max boost
 
dodge sprinter 2500 , 2006 high roof and 158''

the max boost i got was 19, is it ok or should be higher.

the speed 127 km/h and the boost was always going down then back up againn and repeat. is it because reach max speed of my sprinter.

had only about 300 lb in cargo.

calbiker 07-08-2019 04:51 PM

Re: what is max boost
 
Units behind 19 are??

Not sure what max is, but I see 35 psi.

mickal 07-08-2019 05:08 PM

Re: what is max boost
 
The dial is 0 to +22 and other side 0 to -22


Will sélect a display in PSI next time

Midwestdrifter 07-08-2019 05:12 PM

Re: what is max boost
 
19psi boost (35 map) is normal at sea level.

marklg 07-08-2019 05:19 PM

Re: what is max boost
 
I believe max boost is about 20 psi. That will happen on hard acceleration. Normal operation will be lower. It will vary from almost 0 to 20 depending on driving conditions. Most often it will be between 5 and 15 psi.

Regards,

Mark

Aqua Puttana 07-08-2019 06:07 PM

Re: what is max boost
 
Upon acceleration my 2004 with mechanical boost gauge will spike up to around 22 psi briefly, and then immediately settle back to the 19 psi mentioned, or typically even lower. When in the correct gear, even when climbing grades the boost pressure settles back.

The mechanical boost gauge reading is not affected by altitude like the MAP reading is.

:2cents: vic

autostaretx 07-08-2019 06:12 PM

Re: what is max boost
 
When testing the intake plumbing for leaks, MB's recommended maximum inflation pressure is 20 psi (above ambient).

The Sprinter actually *measures* Absolute pressure: so the sea-level range is from 14.7 to 32 (ish) psi
That corresponds to a "boost" of zero to 17+ psi ("boost" is what's called "gauge" pressure in the engineering biz)

--dick
p.s. the cylinders don't know nor care about ambient pressure ... they only care about what's crammed down their throats by the turbo system. The sensor plugged into the intake plumbing is an absolute sensor.
p.p.s. ... and is fun to use as a barometric altimeter: when parked up on Bryce Canyon's 9500' ridge, i'll see 11.5 psi before i start cranking the engine.

calbiker 07-08-2019 06:20 PM

Re: what is max boost
 
Looks like Mercedes C3 scanner defines boost pressure differently. Without engine running, boost pressure is equal to atmospheric pressure.

Midwestdrifter 07-08-2019 06:25 PM

Re: what is max boost
 
Boost is gauge pressure, MAP is absolute. We generally only care about boost, as we are concerned with turbo operation. The ECM needs MAP, to compare to air mass readings.

marklg 07-08-2019 06:28 PM

Re: what is max boost
 
1 Attachment(s)
The Autel provides three pressure sensor readings:

Attachment 115000

As I understood it, the vehicle subtracts the readings from two sensors to determine what it thinks the boost is. I think it is the boost and atmospheric sensors, but there are three to choose from it seems.

Regards,

Mark


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